The present invention relates to a dissolution testing apparatus with a rinsing stand at least one measuring ring vessel being reciprocable with respect to the rinsing stand and the test stand lifted position of the paddle and the rinsing paddle, wherein the means with on one hand one or several measuring vessel(s) and on the other hand rinsing stand and test stand are and suction pipe including a filter by means of which the liquid containing the substance to be examined with respect to the dissolution behaviour thereof can be extracted, the suction pipe therein being lifted and lowered relative to the measuring vessel.
The present invention in particular relates to a dissolution testing apparatus in which an exchange of filters between different measuring cycles is simplified and, in one preferred embodiment, is carried out entirely automatically.
A generic dissolution testing apparatus is generally available. Such dissolution testing apparatus serves for the investigation of the dissolution behaviour of a substance in a liquid and in particular for analyzing the dissolution behaviour of a medical tablet in a liquid, the composition of which essentially corresponds to that of gastric acid.
The know dissolution testing apparatus includes a rinsing stand, a test stand and a movable means carrying a plurality of measuring vessels in a water bath. The rinsing stand comprises a rinsing paddle for each measuring vessel, such paddle being driven with a rotary movement and being arranged as to permit lifting and lowering in a vertical direction. The test stand comprises a paddle for stirring the measuring liquid for each measuring vessel. All of the paddles can be driven in a rotary movement and can be lowered into the measuring vessels containing the substance to be examined as to the dissolution behaviour for stirring the liquid in the vessels. Furthermore, in this known dissolution testing apparatus a suction pipe is provided for each measuring vessel, such suction pipe together with corresponding paddle is submersible into the liquid containing the substance to be examined. The movable means, including the measuring vessels disposed in a water bath, can be driven in a horizontal direction to the position of the rinsing stand. In this position of the movable means, lowering of the rinsing paddles is effected for the purpose of rinsing the measuring vessels. Once the measuring vessels having been cleaned the rinsing paddles are lifted so that the movable means can be moved back to the position of the test stand. When this position is reached the paddles can be lowered into the measuring vessels for evenly stirring the liquid into which, at a given point of time, the substance to be examined is introduced. After a given period of stirring, the liquid is drawn off from the measuring vessels by means of the suction pipes. Such a cycle having been completed it will become necessary to exchange the filters located at the end portions of the suction pipes with new filters, which on one hand requires a good deal of expenditure of labor and on the other hand demands a staff having to be instructed and trained at least to a certain degree.